Method for metalizing polymer substrate and polymer article prepared thereof

ABSTRACT

A method for metalizing a polymer substrate and a polymer article prepared thereof. First, a polymer substrate having a base polymer and at least one metal compound dispersed in the base polymer is provided. Then, a surface of the polymer substrate is irradiated with an energy beam such that a water contact angle of the surface of the polymer substrate is at least 120°. The surface of the polymer substrate is then subjected to chemical plating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/CN2015/071674, filed on Jan. 27, 2015, which isbased on and claims priority to and benefits of Chinese PatentApplication Nos. 201410040525.8, 201410040821.8 and 201410041075.4, allfiled with the State Intellectual Property Office of P. R. China on Jan.27, 2014. The entire contents of the above-identified applications areincorporated herein by reference.

FIELD

Embodiments of the present disclosure relate to a polymer metallizationfield, and more particularly to a method for metalizing a polymersubstrate and a polymer article prepared by the method.

BACKGROUND

The technique of forming a metal layer on a polymer substrate in orderto transmit electro-magnetic signals is widely used in fields likeautomobiles, computers, communications, etc. Selectively forming themetal layer on the surface of the polymer substrate is a key step inthis technique.

One method for selectively metalizing a surface of a polymer substrateincludes the following steps. First, a catalyst or accelerator forchemical plating is adhered on the surface of the polymer substratewhich is to be plated. Then, metal ions in a metal solution for chemicalplating are reduced to pure metal via an oxidation-reduction reaction,and the pure metal are deposited on the surface of the polymersubstrate, thus forming a metal layer on the polymer substrate.

For example, Chinese Patent Application No. CN102752962A discloses asubstrate provided with a metal layer and a manufacturing method of thesubstrate provided with the metal layer. The manufacturing methodincludes the steps of forming a hydrophilic region or a hydrophobicregion on a surface of the substrate by performing surface treatmentwith plasma, and attaching a catalyst layer or an exchange layer or anisolating layer formed by organic or inorganic substances on thehydrophilic or hydrophobic surface of the substrate by using a surfacetreatment solution; then using a metal solution to form the metal layeron the surface of the catalyst layer or the exchange layer due tocatalytic reaction or exchange reaction. The isolating layer can protectother regions from metal deposition, and the metal layer attached to thesubstrate can be patterned, so as to be used as a circuit contact orline. The manufacturing method, however, has disadvantages ofcomplicated processing steps and weak adhesion between the metal layerand the polymer substrate.

Another method for selectively metalizing a surface of a polymersubstrate includes the following steps. First, a polymer material ismixed with a catalyst or an accelerator for chemical plating or aprecursor thereof, and molded to form a polymer substrate with thecatalyst or accelerator or precursor thereof dispersed therein. Beforethe step of chemical plating, a surface of the polymer substrate isirradiated with an energy beam such as a laser, such that a part ofpolymer material in the irradiated surface is gasified and the catalystor accelerator or precursor thereof is exposed. Then, chemical platingis performed on the irradiated surface to form a metal layer on thesurface of the polymer substrate. In case the precursor is used, theprecursor can be activated by the energy beam to form the catalyst oraccelerator.

For example, U.S. Patent Application Publication No. 2004/0241422A1discloses a method for preparing a polymer article, which includes stepsof: adding an inorganic compound having a spinel structure andcontaining Cu, Ni, Co, Cr, Fe, etc. to a polymer matrix, and activatingthe inorganic compound with an ultraviolet laser (with wavelengths of248 nm, 308 nm, 355 nm, 532 nm) and an infrared laser (with wavelengthsof 1064 nm and 10600 nm). Specifically, it is mentioned that the oxideshaving spinel structures should be reduced into metal under the effectof the laser. Then, the metal may act as a crystal core, onto whichmetal may be deposited during a chemical plating process so as to form ametal layer. However, the energy of the laser has to be high enough toreduce the oxides having the spinel structure into pure metal.Therefore, the method has on the one hand serious damage on the polymermatrix, and on the other hand the adhesion between the metal layer andthe substrate is weak.

As another example, Chinese Patent Application No. CN103313523Adiscloses a manufacturing method for an electronic circuit. Themanufacturing method includes the following steps of: preparing acircuit carrier, wherein the circuit carrier is made of a high-molecularcompound and a water repellent agent is added in the high-molecularcompound; carrying out selective electromagnetic irradiation on thesurface of the circuit carrier to form a hydrophilic area; and carryingout electroplating or chemical plating on the circuit carrier to enablea metal material to be attached in the hydrophilic area and form theelectronic circuit.

As described above, methods for selectively metalizing a surface of apolymer substrate still need to be modified. In terms of these methods,it is generally believed that the oxidation-reduction reaction mainlytakes place on the hydrophilic surface, while it is difficult to form acomplete metal layer on the hydrophobic surface.

SUMMARY

Embodiments of the present disclosure seek to solve at least one of theproblems existing in the prior art to at least some extent.

Embodiments of a first broad aspect of the present disclosure provide amethod for metalizing a polymer substrate. The method for metalizing apolymer substrate according to embodiments of the present disclosure mayinclude steps of: providing a polymer substrate having a base polymerand at least one metal compound dispersed in the base polymer;irradiating a surface of the polymer substrate with an energy beam suchthat a water contact angle of the surface of the polymer substrate is atleast 120°; and performing chemical plating on the surface of thepolymer substrate. In some embodiments, the base polymer contains apolymer having an ester and/or amide group in a backbone, and the metalcompound includes those represented by formulas (I), (II), and (III):(Cu_(a)M¹ _(1-a))₃(PO₄)₂ (I), where M¹ includes at least one elementselected from group IIA, i.e. column 2, of periodic table of elements,0<a≦1; (Cu_(b)M² _(1-b))₂(OH)PO₄ (II), where M² includes at least oneelement selected from group IIA of periodic table of elements, 0<b≦1;and (Cu_(c)M³ _(1-c))₂P₂O₇ (III), where M³ includes at least one elementselected from group IIA of periodic table of elements, 0<c≦1.

With the method for metalizing a polymer substrate according toembodiments of the present disclosure, the plating speed during thechemical plating step may be fast. In addition, the adhesion between ametal layer formed on the surface of the polymer substrate and thepolymer substrate may be strong.

Embodiments of a second broad aspect of the present disclosure provide apolymer article prepared by the above-identified method. The polymerarticle according to embodiments of the present disclosure may includethe polymer substrate and at least one metal layer formed on the surfaceof the polymer substrate. In some embodiments, the metal layer forms apredetermined pattern.

According to some embodiments of the present disclosure, thepredetermined pattern corresponds to a structure of a circuit. With themetal layer formed as the predetermined pattern on the surface of thepolymer substrate, the metal layer may act as a circuit for transmittingsignals in various fields, such as communication field. In addition, theadhesion between the metal layer and the polymer substrate may bestrong.

Additional aspects and advantages of embodiments of present disclosurewill be given in part in the following descriptions, become apparent inpart from the following descriptions, or be learned from the practice ofthe embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of embodiments of the presentdisclosure will become apparent and more readily appreciated from thefollowing descriptions made with reference to the accompanying drawings,in which:

FIG. 1 is a flow chart of a method for metalizing a polymer substrateaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the presentdisclosure. The embodiments described herein with reference to drawingsare explanatory, illustrative, and used to generally understand thepresent disclosure. The embodiments shall not be construed to limit thepresent disclosure.

For the purpose of the present description and of the following claims,the definitions of the numerical ranges always include the extremesunless otherwise specified.

According to embodiments of a first aspect of the present disclosure, amethod for metalizing a polymer substrate is provided. The method formetalizing a polymer substrate according to embodiments of the presentdisclosure may include steps of: providing a polymer substrate having abase polymer and at least one metal compound dispersed in the basepolymer; irradiating a surface of the polymer substrate with an energybeam such that a water contact angle of the surface of the polymersubstrate is at least 120°; and performing chemical plating on thesurface of the polymer substrate. In some embodiments, the base polymercontains a polymer having an ester and/or amide group in a backbone, andthe metal compound includes those represented by formulas (I), (II), and(III): (Cu_(a)M¹ _(1-a))₃(PO₄)₂(I), where M¹ includes at least oneelement selected from group IIA of periodic table of elements, 0<a≦1;(Cu_(b)M² _(1-b))₂(OH)PO₄ (II), where M² includes at least one elementselected from group IIA of periodic table of elements, 0<b<1; and(Cu_(c)M³ _(1-c))₂P₂O₇ (III), where M³ includes at least one elementselected from group IIA of periodic table of elements, 0<c≦1.

The inventors of the present disclosure have found that, irradiation ofa surface of a polymer substrate having catalysts or accelerators orprecursors thereof dispersed therein may provide the irradiated surfacewith activity that enables metals to deposit on this irradiated surfacein a chemical plating step. If the irradiation condition is such thatthe irradiated surface has a water contact angle of at least 120° C.,the irradiated surface has not only the capability for chemical plating,the adhesion between metals deposited on the polymer substrate (i.e. ametal player formed therefrom) and the polymer substrate may bestronger.

As shown in FIG. 1, the method for metalizing a polymer substrateaccording to embodiments of the present disclosure may include stepsS1-S3.

In the step S1, a polymer substrate having a base polymer and at leastone metal compound dispersed in the base polymer is provided.

In some embodiments, the polymer substrate is provided by molding amixture of the base polymer and the at least one metal compound.

In some embodiments the base polymer contains a polymer having an estergroup (i.e.

and/or an amide group (i.e.

in a backbone. By way of example and without limits, the polymer havingan ester group and/or amide group in the backbone includes a polyesterand a polyamide. The polyester may refer to a polymer having an estergroup in a backbone, and the polymer may be a copolymer or ahomopolymer. The copolymer having an ester group in a backbone may beobtained by copolymerizing monomers capable of forming an ester groupwith monomers being not capable of forming an ester group. The polyamidemay refer to a polymer having an amide group in a backbone, and thepolymer may be a copolymer or a homopolymer. The copolymer having anamide group in a backbone may be obtained by copolymerizing monomerscapable of forming an amide group with monomers being not capable offorming an amide group.

By way of example and without limits, the polymer having an ester and/oramide group in the backbone may include at least one selected from agroup including: polycarbonate, poly(1,4-cyclohexylenedimethyleneterephthalate), poly(diallyl isophthalate), poly(diallyl terephthalate),poly(butylene naphthalate), poly(ethylene terephthalate), poly(butyleneterephthalate), poly(hexamethylene terephthalamide), poly(nonamethyleneterephthalamide), poly(hexamethylene adipamide), poly(hexamethyleneazelamide), poly(hexamethylene succinamide), poly(hexamethylenelauramide), poly(hexamethylene sebacamide), poly(decamethylenesebacamide), poly(undecanoic amide), poly(lauramide), poly(octanamide),poly(9-aminononanoic acid), polycaprolactam, poly(phenyleneterephthalamide), and poly(hexamethylene isophthalamide).

The amount of the polymer having an ester and/or amide group in thebackbone may be determined based on the type of the polymer. In someembodiments, based on the total weight of the base polymer, the contentof the polymer having an ester and/or amide group in the backbone is atleast 50 wt %. Alternatively, based on the total weight of the basepolymer, the content of the polymer having an ester and/or amide groupin the backbone is at least 70 wt %. In this way, the adhesion between ametal layer formed in the subsequent chemical plating step and thepolymer substrate may be stronger. Further alternatively, based on thetotal weight of the base polymer, the content of the polymer having theester and/or amide group in the backbone is 100 wt %.

In some embodiments, in addition to the polymer having an ester and/oramide group in the backbone, the base polymer contains a polymer nothaving an ester and/or amide group in a backbone, which may be anyconventional polymers. In some embodiments, the polymer not having anester and/or amide group in the backbone may include at least oneselected from a group including: polyolefin (such as polystyrene,polypropylene, poly(methyl methacrylate) andpoly(acrylonitrile-butadiene-styrene)), poly(aromatic ether), polyetherimide, polyphenylene oxide, polyphenylene sulphide, polyimide,polysulfone, poly(ether-ether-ketone), polybenzimidazole, phenolformaldehyde resin, urea formaldehyde resin, melamine-formaldehyderesin, epoxide resin and polyurethane. In some embodiments, thepolyolefin may be modified to improve the compatibility between thepolyolefin and the polymer having an ester and/or amide group in thebackbone. For example, the polyolefin may be modified using maleicanhydride. The polymer having an ester and/or amide group in thebackbone and the polymer not having an ester and/or amide group in thebackbone may be mixed in a conventional way. Generally, these twopolymers may be mixed by forming a polymer alloy.

In some embodiments, the metal compound includes those represented byformulas (I), (II), and (III):

(Cu_(a)M¹ _(1-a))₃(PO₄)₂  (I),

where M¹ includes at least one element selected from group IIA ofperiodic table of elements, for example, selected from Ca, Mg, Ba, andSr, 0<a≦1;

(Cu_(b)M² _(1-b))₂(OH)PO₄  (II),

where M² includes at least one element selected from group IIA ofperiodic table of elements, for example, selected from Ca, Mg, Ba, andSr, 0<b≦1; and

(Cu_(c)M³ _(1-c))₂P₂O₇  (III),

where M³ includes at least one element selected from group IIA ofperiodic table of elements, for example, selected from Ca, Mg, Ba, andSr, 0<c≦1.

In an embodiment, 0.1≦a≦1. In an embodiment, 0.1≦b≦1. In an embodiment,0.1≦c≦1.

The Periodic Table of Elements used herein is the IUPAC version of theperiodic table of elements described in the CRC Handbook of Chemistryand Physics, 90^(th) Edition, CRC Press, Boca Raton, Fla. (2009-2010).

In some embodiments, the metal compound includes at least one selectedfrom a group including: Cu_(2.7)Mg_(0.3)(PO₄)₂, Cu_(1.5)Mg_(1.5)(PO₄)₂,Cu_(1.5)Ba_(0.75)Sr_(0.75)(PO₄)₂, Cu_(0.15)Mg_(2.8)(PO₄)₂,Cu₁₅Ca_(1.5)(PO₄)₂, Cu_(0.15)Ca_(2.85)(PO₄)₂, Cu₂Ba(PO₄)₂,Cu_(0.4)Sr_(2.6)(PO₄)₂, Cu_(0.4)Sr_(2.6)(PO₄)₂, Cu₂P₂O₇, Cu₃(PO₄)₂ andCu₂(PO₄)(OH).

In some embodiments, the metal compound may have a light colour, such aslight green or light blue. Then, a polymer article which is preparedusing the metal compound may show a light colour.

The metal compound may be commercially available, or prepared by anyconventional method in the related art. In some embodiments, the metalcompound may be obtained by sintering a mixture containing a Cu source,a phosphate, and an optional M¹, M² and/or M³ sources.

The Cu source may be CuO and/or any material which is capable of formingCuO under sintering. The material capable of forming CuO under sinteringincludes various Cu salts, such as Cu salts of inorganic acids and/or Cusalts of organic acids. By way of example and without limits, thematerial capable of forming CuO under sintering includes copper oxalateand/or copper carbonate.

The M¹, M² and M³ sources may be corresponding metal oxides thereofand/or any material which is capable of forming the corresponding metaloxides thereof under sintering. The material capable of forming thecorresponding metal oxides thereof under sintering includescorresponding metal salts of inorganic acids and/or corresponding metalsalts of organic acids. By way of example and without limits, thematerial capable of forming corresponding metal oxides under sinteringincludes corresponding metal oxalates and/or corresponding metalcarbonates. For example, the material capable of forming a M¹ oxideunder sintering includes M¹ oxalate and/or M¹ carbonate.

The phosphate may be any conventional metal phosphate and/or ammoniumsalt of phosphoric acid. By way of example and without limits, thephosphate includes ammonium hydrogen phosphate and/or ammoniumdihydrogen phosphate.

There are no particular limits for the relative ratio between the Cusource, the phosphate, and the optional M¹, M² and/or M³ sources,provided contents of various elements in the metal compound satisfiesthe requirements mentioned above.

In some embodiments, the sintering may be performed using a single-stagesintering process or a two-stage sintering process. In the single-stagesintering process, a mixture containing the Cu source, the phosphate,and the optional M¹, M² and/or M³ sources is sintered at a temperatureranging from about 900° C. to about 1000° C. for about 10 h to about 20h, then the sintered mixture was grinded. In the two-stage sinteringprocess, firstly, the mixture containing the Cu source, the phosphate,and the optional M¹, M² and/or M³ sources is sintered at a temperatureranging from about 600° C. to about 900° C. for about 2 h to about 10 h,then the sintered mixture was grinded, and finally the grinded productis heated at a temperature ranging from about 900° C. to about 1000° C.for about 10 h to about 20 h.

In some embodiments, the mixture containing the Cu source, thephosphate, and the optional M¹, M² and/or M³ sources is obtained bygrinding the Cu source, the phosphate, and the optional M¹, M² and/or M³sources.

In some embodiments, the grinding may be performed by a dry grindingprocess, a semi-dry grinding process or a wet grinding process,preferably a semi-dry grinding process or a wet grinding process, morepreferably a wet grinding process.

In some embodiments, a dispersant may be applied in the wet grindingprocess. A person with ordinary skill in the art will appreciate thatthere is no particular limit for the dispersant. In some embodiments,the dispersant may be water and/or dehydrated alcohol. There are noparticular limits for the amount of the dispersant in embodiments of thepresent disclosure, which may be any conventional option.

There are no particular limits for the particle diameter of the metalcompound, provided a compact polymer substrate is formed. For example,the metal compound may have a volume average particle diameter of about0.1 μm to about 5 μm, alternatively about 0.4 μm to about 2 μm.

There are no particular limits for the amount of the metal compound inthe polymer substrate, provided at least one metal layer may be formedon the polymer substrate by chemical plating after the polymer substrateis irradiated with the energy beam. In some embodiments, based on thetotal weight of the polymer substrate, the content of the metal compoundmay be about 0.1 wt % to about 30 wt %, alternatively about 5 wt % toabout 30 wt %.

In some embodiments, at least one additive may be added in the polymersubstrate. In other words, the mixture of the base polymer and the metalcompound may further contain at least one additive. In some embodiments,the additive can be, for example, a filler, an antioxidant, and a lightstabilizer and so on. With the addition of the additive, the performanceand property of the polymer article prepared by the method according toembodiments of the present disclosure may be improved, or even newperformances may be provided to the polymer article. There are nospecial limits for the content and the type of the additive, which maybe selected according to, for example, practical requirements.

The filler used as the additive may be any filler which is non-reactiveunder the effect of the energy beam (either physically or chemically),such as laser. In some embodiments, the filler may be at least oneselected from talc and/or calcium carbonate. In some embodiments, thefiller may be glass fiber. With the addition of glass fiber, the depthof a recess, formed by the energy beam such as a laser, in the surfaceof the polymer substrate may be significantly increased, which mayfacilitate the deposition of a metal (for example, copper) during thesubsequent chemical plating process. In some embodiments, the filler mayinclude at least one selected from a group including micro glass bead,calcium sulfate, barium sulfate, titanium dioxide, pearl powder,wollastonite, diatomite, caoline, pot clay, mica, oil shale ash,aluminum silicate, alumina, silica and zinc oxide.

The antioxidant used as the additive may be any conventional antioxidantin the related art. In some embodiments, the antioxidant may contain aprimary antioxidant and a secondary antioxidant. The ratio between theprimary antioxidant and the secondary antioxidant may be appropriatelyselected according to, for example, the type of the antioxidant. In someembodiments, the weight ratio between the primary antioxidant and thesecondary antioxidant may be about 1:1 to about 1:4. In someembodiments, the primary antioxidant may be a hindered phenolantioxidant. By way of example but without limits, in some embodiments,the primary antioxidant may be antioxidant 1098 or antioxidant 1010, inwhich the antioxidant 1098 mainly contains3,3′-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-N,N′-hexamethylenedipropionamideand the antioxidant 1010 mainly contains pentaerythritoltetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). In someembodiments, the secondary antioxidant may be of a phosphite type. Byway of example and without limits, in some embodiments, the secondaryantioxidant may be antioxidant 168, which mainly containstris(2,4-di-tert-butyl-phenyl)phosphite. With the antioxidant, theoxidation resistance of the polymer substrate may be improved, wherebythe life of the polymer substrate may be improved.

In some embodiments, the light stabilizer used as the additive may be ofthe hindered amine type. In some embodiments, the light stabilizer maybe bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate. The light stabilizermay be any known ones in the related art, without special limits in thepresent disclosure.

In some embodiments, the amount of the additive may be appropriatelyselected according to functions and types of the additives. In someembodiments, based on 100 weight parts of the polymer substrate, thecontent of the filler may range from 1 weight part to 40 weight parts,the content of the antioxidant may range from about 0.01 weight parts toabout 1 weight part, the content of the light stabilizer may range fromabout 0.01 weight parts to about 1 weight part.

In some embodiments, the additive may further contain an additive forimproving the processing performance of the prepared polymer article,such as a lubricant. In some embodiments, the lubricant may be at leastone selected from a group including: ethylene/vinyl acetate copolymer(EVA wax), polyethylene (PE wax) and stearate. With the addition of thelubricant, the flowability of the polymer melt may be improved. In someembodiments, based on 100 weight parts of the mixture for forming thepolymer substrate, the content of the lubricant ranges from about 0.01weight parts to about 1 weight part.

For the aim of the present disclosure, other additives or components canbe optionally added to the above polymer substrate in order to adapt itso as to satisfy specific practical requirements. The polymer articlethus obtained should therefore be considered as being included in thescope of the present disclosure.

In some embodiments, the molding step may be performed by anyconventional molding process known in the related art, without speciallimits in the present disclosure. In some embodiments, the molding stepis performed by injection molding. Before the step of injection molding,the mixture may be extruded and granulated. In another embodiment, themolding step is performed by extrusion molding.

In the step S2, a surface of the polymer substrate is irradiated with anenergy beam such that a water contact angle of the surface of thepolymer substrate is at least 120°.

In some embodiments, a predetermined area of the surface of the polymersubstrate is irradiated with an energy beam such that a water contactangle of the surface of the polymer substrate is at least 120°. Then,metal layers formed in the subsequent chemical plating step may form apattern on the surface of the polymer substrate. The pattern may bepredesigned in order to be used as, for example, a circuit for receivingand transmitting signals in the communication field.

With the method for metalizing a polymer substrate according toembodiments of the present disclosure, by irradiating the predeterminedarea, such as the area to be formed into a pattern, of the surface ofthe polymer substrate, on the one hand the base polymer in thepredetermined area is gasified while the metal compound in thispredetermined area is exposed, and on the other hand the water contactangle of the surface of the polymer substrate becomes at least 120°. Theinventors of the present disclosure have found that, when the irradiatedsurface of the polymer substrate has a water contact angle of at least120°, a metal layer may be chemically plated onto the surface of thepolymer substrate, and the adhesion between the metal layer and thepolymer substrate is strong. In some embodiments, the predetermined areaof the surface of the polymer substrate is irradiated with an energybeam such that the water contact angle of the irradiated surface of thepolymer substrate is at least 130°, for example, ranges from about 130°to about 160°. In this way, the adhesion between the metal layer and thepolymer substrate may be stronger. In an embodiment, the irradiatedsurface of the polymer substrate has a water contact angle of at least140°. In another embodiment, the irradiated surface of the polymersubstrate has a water contact angle of below 150°.

The energy beam may include any conventional energy source that causesthe base polymer to gasify and the metal compound to expose. In someembodiments, the energy beam may include at least one of a laser, anelectron beam and an ion beam. There are no particular limits for theenergy beam. The energy beam may be selected in accordance with types ofthe energy beam, the base polymer and the metal compound in the polymersubstrate, provided the irradiated surface of the polymer substrate hasthe water contact angle as described above. In some embodiments, theenergy beam is a laser. In some embodiments, the laser has a wavelengthof about 157 nm to about 10.6 alternatively about 532 nm to about 1064nm. In some embodiments, the laser has a power of about 10 W to about 20W, alternatively about 12 W to about 18 W. In some embodiments, thelaser has a scanning speed of about 500 mm/s to about 8000 mm/s,alternatively about 4000 mm/s to about 6000 mm/s. In an embodiment,conditions of the laser includes: a step of about 3 μm to about 20 μm, atime delay of about 20 μs to about 100 μs, a frequency of about 10 kHzto about 400 kHz, and a filling spacing of about 10 μm to about 50 μm.

In the step S3, the surface of the polymer substrate is subjected tochemical plating.

In some embodiments, the method may further include a step of cleaningthe surface of the polymer substrate, before the step S3. The cleaningstep may be performed using any conventional cleaning process in therelated art, such that residues and dirt adhered on the surface of thepolymer substrate may be removed.

There are no particular limits for the chemical plating in embodimentsof the present disclosure, and techniques and conditions of the chemicalplating are well known to a person having ordinary skill in the art. Insome embodiments, the chemical plating may be carried out with thefollowing steps. The irradiated polymer substrate is immersed in anelectroless Cu solution. In some embodiments, the electroless Cusolution may contain a Cu salt and a reducing agent and have a pHranging from about 12 to about 13. The reducing agent may reduce Cu ionsin the Cu salt into Cu metal. In some embodiments, the reducing agentmay be at least one selected from a group including: glyoxylic acid,hydrazine, and sodium hypophosphite.

In some embodiments, the method may further include a step ofelectroplating or chemical plating, after the step S3. Theelectroplating or chemical plating may be performed for at least onetimes, so that additional metal layers, either of the same metal as orof different metal from the prior metal layers, may be formed on theprior metal layers. In some embodiments, a Cu layer is formed on thesurface of the polymer substrate in the first chemical plating step(i.e. the step S3), then a Ni layer is formed on the Cu layer in thesubsequent electroplating or chemical plating. With the additional Nilayer, oxidation of the Cu layer may be prevented.

With the method for metalizing a polymer substrate according toembodiments of the present disclosure, the adhesion between the polymersubstrate and the metal layer is stronger, compared with the adhesionbetween the polymer substrate and the metal layer having the samethickness and formed by a conventional method. Therefore, metal layersformed on the predetermined area of the surface of the polymer substratemay act as a more reliable circuit.

Embodiments of another aspect of the present disclosure provide apolymer article prepared by the method for metalizing the polymersubstrate mentioned above. The polymer article according to embodimentsof the present disclosure includes the polymer substrate and at leastone metal layer formed on the surface of the polymer substrate. In someembodiments, the metal layer forms a predetermined pattern.

It will be understood that the features mentioned above and those stillto be explained hereinafter may be used not only in the particularcombination specified but also in other combinations or on their own,without departing from the scope of the present disclosure.

Some illustrative and non-limiting examples are provided hereunder for abetter understanding of the present disclosure and for its practicalembodiment.

Test 1. Method Composition

The composition of the metal compound was measured by an inductivelycoupled plasma—atomic emission spectrometry (ICP-AES).

Water Contact Angle

The water contact angle of the irradiated surface of the polymersubstrate was determined using an OCA20 contact angle testercommercially available from DATAPHYSICS Inc., Germany. 5 μL droplet ofwater was placed on a surface of the sample to be tested (i.e. theirradiated surface of the polymer substrate) using a syringe needle, andthe droplet and the irradiated surface were imaged into a computer usingan optical camera. Then, the water contact angle between the droplet andthe irradiated surface was calculated. For each sample, 5 water contactangles were calculated, and the average value of the 5 water contactangles was recorded as the water contact angle of the irradiated surfaceof the polymer substrate.

Volume Average Particle Diameter

The volume average particle diameter of the metal compound wasdetermined by a Laser Particle Sizer commercially available from ChengduJingxin Powder Analyse Instrument Co., Ltd., China.

Adhesion

The adhesion between the metal layer and the polymer substrate wasdetermined by a cross-cut process. Specifically, a surface of the sampleto be measured was cut using a cross-cut knife to form 100 grids (1 mm×1mm). A gap between adjacent grids was formed to reach the bottom of themetal layer. Debris in the test region was cleaned using a brush, andthen an adhesive tape (3M600 gummed paper) was sticked to grids in thetest region. One end of the sticked adhesive paper was rapidly torn offin a vertical direction. Two identical tests were performed on the samegrid region. The result of the adhesion was determined according to thefollowing standard.

Grade 5B: the cut edge is smooth, and neither metal layers at the cutedge nor metal layers at the cut intersection of the grid peel off.

Grade 4B: the metal layers at the cut intersection partially peel off,but no more than 5% (area percent) of the metal layers peel off.

Grade 3B: the metal layers both at the cut edge and the cut intersectionpartially peel off, and 5% to 15% (area percent) of the metal layerspeel off.

Grade 2B: the metal layers at both the cut edge and the cut intersectionpartially peel off, and 15% to 35% (area percent) of the metal layerspeel off.

Grade 1B: the metal layers at both the cut edge and the cut intersectionpartially peel off, and 35% to 65% (area percent) of the metal layerspeel off.

Grade 0B: the metal layers at both the cut edge and the cut intersectionpartially peel off, and more than 65% (area percent) of the metal layerspeel off.

The results are shown in Table 1.

2. Examples Example 1

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includes thefollowing steps.

1) Preparation of Polymer Substrate

Polycarbonate (PC), Cu₂P₂O₇ (commercially available from Shanghai ZiyiReagent Factory, China, having a color of light green and an averageparticle diameter of 1.5 μm), antioxidant 1076 and EVA wax having aweight ratio of 100:5:0.5:0.2 were mixed in a high-speed mixer to form amixture, then the mixture was extruded and granulated in a twin screwextruder (from Nanjing Rubber and Plastics Machinery Plant Co., Ltd.,China), and the granulated material was injection molded to obtain apolymer substrate having a size of 125 mm×15 mm×3 mm.

2) Irradiation

A rectangular area having a dimension of 15 mm×8 mm of a surface of thepolymer substrate was irradiated with an infrared laser (DPF-M12 fromShenzhen TETE Laser Technology Co., Ltd., China) under laser conditionsof: a wavelength of 1064 nm, a scanning speed of 2000 mm/s, a step of 9μm, a time delay of 20 μs, a frequency of 60 kHz, a power of 12 W, and afilling spacing of 50 μm. After that, the irradiated polymer substratewas cleaned with an ultrasonic cleaner and dried. The water contactangle of the irradiated surface of the polymer substrate was recorded inTable 1.

3) Chemical Plating

The polymer substrate obtained from the step 2) was subjected tochemical plating in an electroless Cu solution at 53° C. to form a Culayer having a thickness of 3 μm on the irradiated surface of thepolymer substrate. Then, the temperature of the electroless Cu solutionwas decreased to 45° C. and the chemical plating was continued, untilthe thickness of the Cu layer reached 13 μm. The polymer substrateformed with the Cu layer was subsequently subjected to chemical platingin an electroless Ni solution to form a Ni layer having a thickness of 3μm on the Cu layer. Then, the polymer substrate formed with the Ni layerwas subjected to flash plating in a gold solution to form a gold layerhaving a thickness of 0.03 μm on the Ni layer. The plating speed duringchemical plating of Cu was listed in Table 1.

The electroless Cu solution contained 0.12 mol/L CuSO₄.5H₂O, 0.14 mol/LNa₂EDTA.2H₂O, 10 mg/L potassium ferrocyanide, 10 mg/L 2,2′-bipyridine,and 0.10 mol/L glyoxylic acid. The electroless Cu solution had a pH of12.5 to 13 which was adjusted with NaOH and H₂SO₄.

The electroless Ni solution contained 23 g/L nickel sulphate, 18 g/Lsodium hypophosphite, 20 g/L lactic acid, and 15 g/L malic acid. Theelectroless Ni solution had a pH of 5.2 which was adjusted with NaOH.

The gold solution was BG-24 neutral gold solution commercially availablefrom Shenzhen Jingyanchuang Chemical Co., Ltd., China.

The adhesion between metal layers and the polymer substrate was recordedin Table 1.

Example 2

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the power of the laser was 10 W (instead of 12 W) in the step 2).

Comparative Example 1

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the power of the laser was 8 W (instead of 12 W) in the step 2).

Comparative Example 2

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the rectangular area of the surface of the polymer substrate waspolished (instead of being irradiated with laser) firstly with a 200#sandpaper and then with a 1500# sandpaper, and a recess formed in thepolished area of the surface of the polymer substrate had a depth of 20μm.

Comparative Example 3

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the rectangular area of the surface of the polymer substrate wassubjected to a sand blasting process (instead of being irradiated withlaser) under conditions of: a sand of 150# white corundum, a sandblasting temperature of 40° C., a pressure of 80 psi, and a time periodof 8 s.

Comparative Example 4

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the rectangular area of the surface of the polymer substrate wassubjected to chemical etching (instead of being irradiated with laser)under conditions of: 5 wt % NaOH solution as an etching solution and anetching time of 30 min.

Comparative Example 5

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat maleic anhydride modified propylene (PP) in the same weight percentas PC was used instead of PC in the step 1).

The maleic anhydride modified PP was obtained by mixing PP, maleicanhydride (commercially available from Shanghai Ziyi Reagent Factory,China), and dicumyl peroxide having a weight ratio of 100:3:1 in ahigh-speed mixer to form a mixture, and extruding and granulating themixture in a twin screw extruder (from Nanjing Rubber and PlasticsMachinery Plant Co., Ltd., China).

Comparative Example 6

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includes thefollowing steps.

1) Preparation of Polymer Film

Pyromellitic dianhydride (PMDA), diamino diphenyl ether (ODA), Cu₂P₂O₇,and N,N-dimethyl acetamide (DAMC) having a weight ratio of 4:2.6:1:31were used for preparing a polymer film with the following steps.Firstly, 256 g of DMAC was placed in a 1000 mL flask at 25° C., and 30 gof ODA was added into the flask under stirring. The stirring was keptfor 1 h until the ODA was dissolved completely. Then, 35.76 g of PMDAwas added into the flask under stirring, and the stirring was kept for 1h. After that, 11.2 g of Cu₂P₂O₇ was added into the flask understirring, and the stirring was kept for 30 min. Finally, the remainingPMDA was added into the flask to form a mixture having a viscosity ofabout 50000 mPa·s (25° C.).

The mixture was poured onto a 316 stainless steel strip to form a wetfilm. The stainless steel strip having the wet film thereon was heatedin a furnace, and the temperature in the furnace was increased from 90°C. to 140° C. in 30 min. After the film peeled from the stainless steelstrip, it was nailed on a stenter frame (heating furnace), with an edgeof the film fixed.

Then, the film nailed on the stretching frame was heated to dryness(solid content >99 wt %), and the film passed through a drying box whosetemperature was increased from 200° C. to above 360° C. in 30 min, so asto imidize the film and thus obtain a polymer film (polyimide film). 2)Irradiation

The polymer film was subjected to the same irradiation as the step 2) ofExample 1.

3) Chemical Plating

The polymer film was subjected to the same chemical plating as the step3) of Example 1.

Example 3

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat a mixture of PC and maleic anhydride modified PP (prepared by thesame process as described in Comparative Example 5) in the same weightpercent as PC was used instead of PC in the step 1), and the weightratio between the PC and the maleic anhydride modified PP in the mixturewas 1:1.

Example 4

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat a mixture of PC and maleic anhydride modified PP (prepared by thesame process as described in Comparative Example 5) in the same weightpercent as PC was used instead of PC in the step 1), and the weightratio between the PC and the maleic anhydride modified PP in the mixturewas 7:3.

Comparative Example 7

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat Cu₂P₂O₇ was not used in the step 1).

The results indicate that it is impossible to form metal layers on thepolymer substrate.

Example 5

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the mixture was formed by poly(hexamethylene terephthalamide),Cu₃(PO₄)₂ (commercially available from Shanghai Ziyi Reagent Factory,China, having a color of blue and an average particle diameter of 2 μm)and polyethylene wax having a weight ratio of 100:5:0.2 (instead of amixture formed by PC, Cu₂P₂O₇, antioxidant 1076 and EVA wax having aweight ratio of 100:5:0.5:0.2) in the step 1).

Example 6

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the mixture was formed by PC, poly(ether-ether-ketone) (PEEK),Cu₂(PO₄)(OH) (commercially available from Shanghai Aoke Industries Co.,Ltd., China, having a color of light whitish green and an averageparticle diameter of 1 μm), calcium silicate fiber, antioxidant 1076 andpolyethylene wax having a weight ratio of 70:30:10:10:0.2:0.1 (insteadof a mixture formed by PC, Cu₂P₂O₇, antioxidant 1076 and EVA wax havinga weight ratio of 100:5:0.5:0.2) in the step 1).

Comparative Example 8

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 6, with the exceptionthat the mixture was formed by PEEK, Cu₂(PO₄)(OH), calcium silicatefiber, antioxidant 1076 and polyethylene wax having a weight ratio of100:10:10:0.2:0.1 (instead of a mixture formed by PC, PEEK,Cu₂(PO₄)(OH), calcium silicate fiber, antioxidant 1076 and polyethylenewax having a weight ratio of 70:30:10:10:0.2:0.1) in the step 1).

Example 7

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the mixture was formed by poly(hexamethylene adipamide),Cu_(0.15)Ca_(2.85)(PO₄)₂, calcium silicate fiber, antioxidant 1076 andpolyethylene wax having a weight ratio of 100:15:5:0.2:0.1 (instead of amixture formed by PC, Cu₂P₂O₇, antioxidant 1076 and EVA wax having aweight ratio of 100:5:0.5:0.2) in the step 1). The preparation ofCu_(0.15)Ca_(2.8)(PO₄)₂ included the following steps.

A mixture of CuO, calcium oxalate and NH₄H₂PO₄ having a molar ratio of0.15:2.85:2 was subjected to wet grinding in a grinding machine to formpowders, using dehydrated alcohol as a dispersant. Based on 100 weightparts of the mixture, the amount of the dehydrated alcohol was 150weight parts. Conditions for grinding included a rotation speed of 500rpm and a grinding time of 5 h.

The powders were dried in an oven in an air atmosphere at a dryingtemperature of 80° C. for 12 h.

The dried powders were sintered in an air atmosphere at a sinteringtemperature of 900° C. in a muffle furnace for 10 h. The sinteredproduct was subjected to dry grinding, and the grinded product wassintered in an air atmosphere at a sintering temperature of 1000° C. ina muffle furnace for 20 h. Then, a metal compound having a light blueishcolor and a volume average particle diameter of 2 μm was obtained. Aftertesting, the metal compound was proved to be Cu_(0.15)Ca_(2.8)(PO₄)₂.

Example 8

The present example provides a method for metalizing a polymer substrateand a polymer article prepared thereof. The method includessubstantially the same steps as those in Example 1, with the exceptionthat the mixture was formed by poly(ethylene terephthalate),Cu_(1.5)Ba_(0.75)Sr_(0.75)(PO₄)₂, antioxidant 1076 and polyethylene waxhaving a weight ratio of 100:20:0.5:0.2 (instead of a mixture formed byPC, Cu₂P₂O₇, antioxidant 1076 and EVA wax having a weight ratio of100:5:0.5:0.2) in the step 1). The preparation ofCu_(L5)Ba_(0.75)Sr_(0.7)(PO₄)₂ included the following steps.

A mixture of CuO, BaCO₃, SrCO₃ and NH₄H₂PO₄ having a molar ratio of1.5:0.75:0.75:2 was subjected to wet grinding in a grinding machine toform powders, using dehydrated alcohol as a dispersant. Based on 100weight parts of the mixture, the amount of the dehydrated alcohol was150 weight parts. Conditions for grinding included a rotation speed of500 rpm and a grinding time of 5 h.

The powders were dried in an oven in an air atmosphere at a dryingtemperature of 80° C. for 12 h.

The dried powders were sintered in an air atmosphere at a sinteringtemperature of 600° C. in a muffle furnace for 10 h. The sinteredproduct was subjected to dry grinding, and the grinded product wassintered in an air atmosphere at a sintering temperature of 1000° C. ina muffle furnace for 15 h. Then, a metal compound having a light greencolor and a volume average particle diameter of 2 μm was obtained. Aftertesting, the metal compound was proved to beCu_(1.5)Ba_(0.75)Sr_(0.7)(PO₄)₂.

TABLE 1 Water Contact Plating Speed Adhesion Angle (°) (μm/h) GradeExample 1 143.5 6.5 5B Example 2 126.3 5.2 4B Comparative Example 1108.2 3.8 1B Comparative Example 2 105.2 1.2 3B Comparative Example 3106.3 1.4 3B Comparative Example 4 108.1 1.3 3B Comparative Example 5105.8 2.5 1B Comparative Example 6 51.6 3.1 2B Example 3 121.9 4.2 4BExample 4 128.2 5.1 4B Example 5 141.8 6.4 5B Example 6 129.2 5.6 4BComparative Example 8 108.2 2.1 1B Example 7 142.8 6.2 5B Example 8143.6 6.4 5B

As can be concluded from Table 1, with the method for metalizing apolymer substrate according to embodiments of the present disclosure,metal layers may be formed on the surface of the polymer substrate bychemical plating. Under the same condition, the plating speed is fasterand the adhesion between the metal layer and the polymer substrate isstronger using the method according to embodiments of the presentdisclosure, compared to conventional methods.

Reference throughout this specification to “an embodiment,” “someembodiments,” “one embodiment”, “another example,” “an example,” “aspecific example,” or “some examples,” means that a particular feature,structure, material, or characteristic described in connection with theembodiment or example is included in at least one embodiment or exampleof the present disclosure. Thus, the appearances of the phrases such as“in some embodiments,” “in one embodiment”, “in an embodiment”, “inanother example,” “in an example,” “in a specific example,” or “in someexamples,” in various places throughout this specification are notnecessarily referring to the same embodiment or example of the presentdisclosure. Furthermore, the particular features, structures, materials,or characteristics may be combined in any suitable manner in one or moreembodiments or examples.

Although explanatory embodiments have been shown and described, it wouldbe appreciated by those skilled in the art that the above embodimentscannot be construed to limit the present disclosure, and changes,alternatives, and modifications can be made in the embodiments withoutdeparting from spirit, principles and scope of the present disclosure.

What is claimed is:
 1. A method for metalizing a polymer substrate,comprising: providing a polymer substrate having a base polymer and atleast one metal compound dispersed in the base polymer, the base polymercomprising a polymer, wherein the metal compound has a formula selectedfrom one of the following formulas (Cu_(a)M¹ _(1-a))₃(PO₄)₂ (I),(Cu_(b)M² _(1-b))₂(OH)PO₄ (II), and (Cu_(c)M³ _(1-c))₂P₂O₇ (III), whereM¹ comprises at least one element selected from group IIA of periodictable of elements, 0<a≦1; M² comprises at least one element selectedfrom group IIA of periodic table of elements, 0<b≦1; and M³ comprises atleast one element selected from group IIA of periodic table of elements,0<c≦1; irradiating a surface of the polymer substrate with an energybeam such that a water contact angle of the surface of the polymersubstrate is at least 120°; and performing chemical plating on thesurface of the polymer substrate.
 2. The method according to claim 1,wherein the polymer substrate is provided by molding a mixture of thebase polymer and the at least one metal compound.
 3. The methodaccording to claim 1, wherein based on the total weight of the polymersubstrate, the content of the metal compound is about 0.1 wt % to about30 wt %.
 4. The method according to claim 1, wherein the metal compoundcomprises at least one selected from a group consisting ofCu_(2.7)Mg_(0.3)(PO₄)₂, Cu_(1.5)Mg_(1.5)(PO₄)₂,Cu_(1.5)Ba_(0.75)Sr_(0.75)(PO₄)₂, Cu_(0.15)Mg_(2.85)(PO₄)₂,Cu_(1.5)Ca_(1.5)(PO₄)₂, Cu_(0.15)Ca_(2.85)(PO₄)₂, Cu₂Ba(PO₄)₂,CuSr₂(PO₄)₂, Cu_(0.4)Sr_(2.6)(PO₄)₂, Cu₂P₂O₇, Cu₃(PO₄)₂ andCu₂(PO₄)(OH).
 5. The method according to claim 1, wherein theirradiating comprises irradiating the surface of the polymer substratewith an energy beam such that the water contact angle of the surface ofthe polymer substrate is at least 130°.
 6. The method according to claim5, wherein the irradiating comprises irradiating the surface of thepolymer substrate with an energy beam such that the water contact angleof the surface of the polymer substrate is about 130° to about 160°. 7.The method according to claim 1, wherein the energy beam comprises atleast one of a laser, an electron beam, and an ion beam.
 8. The methodaccording to claim 7, wherein the laser has a wavelength of about 157 nmto about 10.6 μm.
 9. The method according to claim 7, wherein the laserhas a power of about 10 W to about 20 W.
 10. The method according toclaim 7, wherein the laser has a scanning speed of about 500 mm/s toabout 8000 mm/s.
 11. The method according to claim 1, wherein based onthe total weight of the base polymer, the content of the polymer is atleast 50 wt %.
 12. The method according to claim 1, further comprisingcleaning the surface of the polymer substrate before chemical plating.13. The method according to claim 1, wherein the polymer comprises apolyester.
 14. The method according to claim 1, wherein the polymercomprises a polyamide.
 15. The method according to claim 1, wherein thepolymer comprises an ester group in a backbone.
 16. The method accordingto claim 1, wherein the polymer comprises an amide group in a backbone.17. The method according to claim 1, wherein the polymer comprises anester and amide group in a backbone.
 18. A polymer article prepared bythe method according to claim 1, wherein the polymer article comprisesthe polymer substrate and at least one metal layer formed on the surfaceof the polymer substrate, and the metal layer forms a predeterminedpattern.